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Invasive of the Month
By East Kootenay Invasive Species Council
Cypress spurge (Graveyard weed) was introduced to North America from Europe as an ornamental plant but has since escaped. It prefers sun but tolerates shade as well. It can be found growing in open, disturbed sites like meadows, pastures, and roadsides. It grows quickly and aggressively, releasing chemicals from its roots which stop other plants growing near it. This helps it crowd out native species.
WARNING: Toxic to humans, livestock and wildlife when consumed, or when its sap (latex) contacts skin. The sap causes nausea, vomiting and diarrhea when eaten.
It can cause blindness if it gets in people’s eyes and skin contact causes redness, swelling and blisters.
How to Identify:
Cypress spurge is a perennial herb that can be 10–60 cm tall growing through creeping rhizomes.
Flowers are yellow to green and turn red at maturity.
Leaves are 2.5–three cm long, thin, waxy, and blue-green that spiral around the stem.
Impacts:
Ecological
– Alters native grassland biodiversity;
– Displaces wildlife and livestock by eliminating forage areas due to dense colonies;
– Crowds out pastures;
– Decreases moisture and nutrients in soil.
Social
– Contains a milky latex that can irritate the skin of humans, as well as the skin and mouths of livestock.
Economic
– Reduces the abundance of desirable vegetation;
– Reduces cattle grazing and hay production capacities;
– Reduces the value of pastures; contaminates hay fields.
Management:
Mechanical Control
– Hand-pull infestations when the soil is moist, removing the entire root system.
– Mowing or tilling at regular intervals (every three weeks) can adequately reduce weed progression at first bloom, but this can stimulate new growth if the mowing is not done regularly. Additionally, note that mowing will not eradicate the plant.
Chemical Control
– Annual applications of dicamba or 2,4-D, or monthly applications of glyphosate, have proven effective.
– On small infestations, picloram or a combination of picloram and 2,4-D is also effective.
Biological + Cultural Control
– Flea beetles (Aphthona cyparissiae and A. nigristucus) feed on cypress spurge’s roots, providing control; grazing by sheep and goats has also been reported as successful.
East Kootenay Invasive Species Council photos
